This application claims the benefit of a Japanese Patent Application No. 2002-024236 filed Jan. 31, 2002, in the Japanese Patent Office, the disclosure of which is hereby incorporated by reference.
1. Field of the Invention
The present invention generally relates to access control methods and storage apparatuses, and more particularly to an access control method for controlling access to a storage medium which is recorded with enciphered information and to a storage apparatus which employs such an access control method.
2. Description of the Related Art
In information processing apparatuses such as personal computers, information is recorded in and reproduced from various kinds of storage media. The storage media may roughly be categorized into a fixed type which is fixed within a storage apparatus, and a portable type which is loaded into and unloaded from the storage apparatus. Examples of such storage media include card-shaped or disk-shaped magnetic storage media, optical storage media and magneto-optical storage media, semiconductor memory devices such as RAMs, and the like. The kind of information recorded in and reproduced from such storage media is not limited to a specific kind, and for example, includes document information, image information, audio information, program information or arbitrary combinations of such information.
Conventionally, various methods have been proposed to prevent unauthorized access to the storage medium. For example, there is a proposed method which prohibits access to the storage medium unless the user is confirmed to be a legitimate (or authorized) user by making a password authentication. According to this proposed method, an access to the storage medium cannot be made unless a password input to the personal computer matches a password recorded in the storage medium.
In other words, the information cannot be reproduced from and the information cannot be recorded in the storage medium, unless it is confirmed through password authentication that the user attempting to access this storage medium is the legitimate user. More particularly, if the user is not the legitimate user, a recording and reproducing means for recording information in and reproducing information from the storage medium is controlled to a non-operational state. Accordingly, a third party other than the legitimate user cannot illegally acquire the information recorded in the storage medium. Furthermore, a third party other than the legitimate user cannot illegally record information in the storage medium or erase recorded information from the storage medium.
However, even in the case of the storage medium which requires the password authentication when making access, no measures are taken to prevent reading of the information itself recorded in the storage medium. This is because the access to the storage medium is prohibited by controlling the recording and reproducing means to the non-operational state. For this reason, there is a problem in that, once the storage medium is acquired, a person familiar with physical conditions and the like of the storage medium may read the information recorded in the storage medium using a reading unit or the like with relative ease.
Moreover, there is also another problem in that illegal or unauthorized copies can be created with ease, since the recorded information can be read from the storage medium.
Therefore, with respect to the information recorded in the storage medium, problems related to security or problems related to copyright are generated.